The goals of this project are designed to contribute technical information on which to estimate the contribution of physiological stress to the induction of cancer by viruses and chemicals. Model systems consisting of rodents, felines, and primates as well as cell cultures of these species are being used to evaluate the modification of normal host physiology on subsequent cancer occurrence. In particular, pregnancy, hormonal imbalance, exposure to x-ray and ultraviolet light are being investigated. The function of viral associated proteins on the host immune capacity are being illucidated based on the induction of such viral proteins by altered host physiology.